/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.rpc.akka;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.runtime.akka.AkkaUtils;
import org.apache.flink.util.Preconditions;

import akka.actor.ActorSystem;
import org.junit.rules.ExternalResource;

/**
 * External resource which starts an {@link akka.actor.ActorSystem}.
 */
public class ActorSystemResource extends ExternalResource {

	private final Configuration configuration;

	private ActorSystem actorSystem;

	private ActorSystemResource(Configuration configuration) {
		this.configuration = configuration;
	}

	@Override
	protected void before() throws Throwable {
		Preconditions.checkState(actorSystem == null, "ActorSystem must not be initialized when calling before.");
		actorSystem = AkkaUtils.createLocalActorSystem(configuration);
	}

	@Override
	protected void after() {
		Preconditions.checkState(actorSystem != null, "ActorSystem must be initialized when calling after.");
		AkkaUtils.terminateActorSystem(actorSystem).join();
	}

	public ActorSystem getActorSystem() {
		return actorSystem;
	}

	public static ActorSystemResource defaultConfiguration() {
		return new ActorSystemResource(new Configuration());
	}

	public static ActorSystemResource withConfiguration(Configuration configuration) {
		return new ActorSystemResource(configuration);
	}
}
